Eleven cases of supratentorial neuroepithelial tumor presenting in infancy are reported. The tumors were characterized by their voluminous size, their intense desmoplasia, and the frequent presence of divergent astrocytic and ganglionic differentiation as demonstrated by special neurohistological and immunohisto- and immunocytochemical techniques. All the tumors presented in subjects below the age of 18 months, usually within the first 4 months of life. They most often involved the frontal and parietal regions and were composed predominantly of a dense desmoplastic tissue superficially resembling a moderately cellular fibroma. The fibroblastic elements were admixed with variable numbers of pleomorphic neuroepithelial cells. Divergent astrocytic and neuronal differentiation was demonstrable in nine of the 11 tumors. All showed astrocytic differentiation. The study of one example by electron microscopy, immunocytochemistry, and tissue culture disclosed that the astrocytic tumor cells were partly invested by a pericytoplasmic basal lamina. Successful total or near-total surgical resection has been followed by a favorable postoperative course extending in some cases over many years of tumor-free survival. The name "desmoplastic infantile ganglioglioma" is proposed for this apparently distinct clinicopathological entity, whose massive size is indicative of a pre- or perinatal origin. Its identification can be achieved by careful histological analysis and is of obvious prognostic significance.